EPRI Finds DC Power Uses 15% Less Electricity Than AC System at Duke Energy Data Center

November 16, 2010 by Jeff Shepard

A preliminary test by the Electric Power Research Institute (EPRI) of a dc power system at a Duke Energy data center in Charlotte, North Carolina found that the system uses 15% less electricity than the existing ac power system.

The U.S. Environmental Protection Agency (EPA) reported to Congress that data center industry power consumption doubled from 2000 to 2006 and was expected to double again over the next five years. If this trend continues to 2016, then reducing data centers’ energy consumption could reduce demand more than 25 billion kilowatt hours per year.

"While this is significant news for any company running a data center today, this could be especially critical for the more than 2.5 million smaller data centers across the United States that rely upon inexpensive yet viable ways to reduce costs," said Curtis Watkins in Duke Energy’s Technology Development group. "If this dc technology was implemented in all those data centers the impact could be significant."

For the Duke Energy demonstration project, the data center’s 480Vac was converted to 380Vdc and delivered to the equipment racks via a 380Vdc bus. The 15% energy savings provides a good benchmark for the industry because the 480Vac system configuration is typical for data centers across the United States.

"DC-powered data centers provide increased energy savings by eliminating multiple power conversion stages," said Omar Siddiqui, director of energy utilization research for EPRI. "Through similar circuit elimination, the data center servers are also made more efficient."